Treatment of waste leather, rawhides or skins, hoofs, horns, or bones of animals.



UNITED STATES PATENT OFFICE.

ALEO GAVAN INRI G, OF TOTTENHAM, ENGLAND, ASSIGNOR OF THREE-FOURTHS TO HERBERT EDWARD McKRELL, OEWVESTMINSTER, ENGLAND.

TREATMENT OF WASTE LEATHER, RAWHIDES OR SKINS, HOOFS, HORNS, 0R BONES OF ANIMALS.

Specification of Letters Patent.

Patented July 7, 1908.

Application filed October 5, 1906. Serial r10. 337,646.

To all whom it may concern: 7

Be it known that I, ALEC GAVAN INRIG,

consulting engineer, a subject of the King of useful Improvements in or Relating to the- Treatment of .Waste Leather, Rawhides or Skins, Hoofs, Horns, or Bones of Animals, of which the following is a specification.

This invention relates to the treatmentof A waste leather raw hides or skins hoofs horns the like) and cut into strips or rolls of tape e for lapping electric cables or it may molded and vulcanized for any desired purpose e. g. for electric accumulator cells, or it may be made so as to serve as a-substitute for leather, vulcanite, etc., etc.

According to this invention the material or materials (waste leather, raw hides or skins, hoofs, horns, or bones of animals-or any mixture thereof) are placed in a suitable vessel and boiled for an hour (or more or less as desired) in water to which has been added a small uantity of caustic soda or other suitable akali; the quantity of alkali used being determined by the quality of the material to be treated and is usually from about 3% to 10% or more or less as required. After boiling as aforesaid the mass is allowed to cool and for this purpose it may or may not be removed to another vessel, and in the case of waste leather raw hides or skins it is reduced to a pul by the aforesaid means of heat and an alka i which is a good solvent of leather. The action of the alkali is arrested before the mass has been reduced to a glue; and the mass is then treated with dilute sulfuric acid of suitable density-say 1.200 density or more or less as desired; in this treatment the relative proportion of acid used will be determined by the quantity of alkali that has been applied in the boiling.

About one gallon dilute acid for every 1% of alkali used 1n the boiling process givesa good result. Nextwhen treating waste leather raw hides or skinsa gentle heat is applied to the mass (by means of a steam jet or otherwise and as this mass of waste leather raw hides or skins (all of which for the sake of brevity will hereinafter be referred to as Waste leather) warms up a new. material or substance is formed which separates itself from the water and rises to the surface after the manner of froth and this material isthen skimmed off .(or the water may be drawn off and the material removed) and utilized in any of the following manners For example it may now be thoroughly dried and (with or without further treatment) it may under heat be rolled pressed or molded into any suitable form shape or article desired for instance it may be pressed in hot dies into sheets of any desired thickness for electrical.

or other urposes; or for certain purposes, such as or forming heels for boots. and shoes, parquet blocks, fireproof floorings, partitions, and ceilings etc. the following mixture may be employed 10% or thereabout of waste leather treated and prepared as aforesaid may be mixed with 90% or thereabout of sawdust. .This mixture is then damped with a solution made u of 1% down hot on the wood iron concrete or other surface to be coated or covered, and leveled down with hot irons; or this mixture in the cold state may be placed in any suitable mold or press and ressed or molded under heat (e. g. in hot ies) and so formed into boards or parquet blocks heels for boots and shoes etc. Or before treating the waste leather in the aforesaid manner, such waste leather may have mixed therewith any suitable proportion of other waste materials such as rags of-any descri tion, waste paper, orstraW; such mixture 0 waste leather and such waste material being boiled together in the alkali, and then treated with an acid as hereinbefore described with reference to the waste leather alone; and after leaving the acid tank there is added to this mixture of materials 1% of stannate of soda and 2% of hide glue; and this mixture of materials (when cold) is then thoroughly mixed and ticator or other suitable vesse ma then be utilized as above described wit reference to the mixture of leather and sawdust. Oraccording to a further part of the present invention the new substance or material thus produced from leather waste may be further treated and mixed with bitumen as hereinafter described.

In the case of the leather waste, after same has been subjected to the foregoing.

treatment and the new material or substance obtained as aforesaid (t. e. after the alkali and acid treatment) such material as it rises to the surface is skimmed off (or the water may be drawn off) and the material removed to a suitable vessel which may advantageously be an ordinary steam facketed. masmixed with an e ual or other suitable uantity of Trinidad itumen or the like a vantageously bitumen specially prepared as hereinafter described.

The bitumen used is advantageously thator of the character of thatknown as Trinidad bitumen; a quantity of which is placed in'a suitable boiler and raised to a temperature of 260 to 300 F; and to this bitumen there is then added 20% (or other suitable proportion) of petroleum residuum or anima fat, 15% (or other-suitable proportion) of sulfur, 10% (or other suitable 'proportion) of glutinous material such as orn hoof or bone meal, or glue, etc. This mixture is stirred or agitated for one hour or thereabout and kept at about 300 F. for another hour or thereabout, and is then ready to be mixed with the aforesaid waste leather product in the steam jacketed masticator or other suitable mixin vessel.

After thoroughly mixing this waste leather ture being suitable for molding into accumu lator boxes and other electric insulating purposes, or may be employed for any other desired purposes.

Referring now to the case of horns hoofs and bonesafter same have been subjected 'to the alkali and acid treatmentthe resulting mass (which tends to settle in the vessel and therefore does not rise in the form of a froth as in the case of the Waste leather raw hides or skins) is now passed through a pair of rollers having different peripheral speeds (or through more than one such pair of differential rollers desired) and dried; and

wherein it is I utilized. in any desired e ssaeeo treated with sulfuric acid to neutralize the alkali as hereinbefore described, and the mass thus treated is then reduced to a fine powder by any suitable means for example by re peatedly passing it through rollers having different peripheral speeds and drying it.

This powder is then mixed with about 30% of Trinidad bitumen prepared as aforesaid or the likeand is then thoroughly dried and may now be utilized in any desired manner 6. it may be pressed into sheets rodsor tubes by means of hot dies, under a hydraulic press and the resultin product is'a black or dark substance resembling ebony possessing very high electrical resisting roperties and this mixture of horns hoofs or iiones and prepared Trinidad bitumen is absolutely nonhygroscopic.

This invention is not confined to the exact figures and proportions as hereinbefore described.

ln some cases as for instance with pieces of hard leather such as old-leather soles and cuttings from sole leather or from hydraulic pressed leather it is found advantageous to first immerse such hard pieces of leather in a solution of Water and lime (*i. e. milk'of lime) in Which it is heated and to which is added the alkali as aforesaid; this addition of lime facilitating the softenin of the leather and reducing the length .of time during which it is necessary .to boil it.

What I claim is 1. The herein described process of producing from waste leather raw hides and skins, hoofs, horns or bones a new substance or compound which consists in treating Waste leather etc. first with an alkali under heat arresting the action thereof before a glue is formed and then after cooling the mass treating the latter With a dilute acid, drying the mass, and finally molding it or subjecting it to pressure.

Or accord- 2. Process of producing from waste leather 7 raw hides or skins and chemicals 2. new and useful substance or compound which consistsin reducing such waste leather raw hides or skins to ulp by means of heat and an alkali, cooling 516 mass and arresting the action of the alkali before glue is formed treating the mass with an acid and then again applying heat to the mass and thereby converting the aforesaid materials into a new substance or compound which may then be with the new substance just forme 3. The herein described rocess of producing material in suitable 'orm for heels for boots and shoes fireproof flooring or partitionsor the like or other purposes, which consists in treating waste materials such as leather, raw hides, skins, hoofs, horns or bones, first with alkali under heat, arresting the action thereof beforea glue is formed,

then after cooling the mass, treating the same with dilute acid, then sawdust damping thismixture with a solution of stannate of soda and hide glue the mass being ground and thoroughly mixed and either applled hot to the surface to 'be coated therewith or molded or pressed under'heat into any'suitable form substantially as set forth.

4. Process of producing from waste leather raw hides or skins hoofs horns or bones of animals and chemicals a new and useful sub-- stance which consists in treating wasteleather raw hides or skins hoofs horns or bones with alkali under heat, arresting the action before a glue is formed cooling the mass and treating the same with a dilute acid and mixing the resultant product with bitumen substantially as set forth.

5. Process of producing from waste leather raw hides orskins hoofs horns or bones of,

animals and chemicals a new and useful substance which consists in treating waste leather raw hides or skins hoofs horns orv bones with alkali under heat, cooling the mass and arresting the action of the alkali by treating the mass with an acid and mixin the resulting productwith specially prepared Trinidad bitumen substantially as set forth.

6. The herein described process of roducing a material in a suitable form for eels of boots and like articles which consists in treatingwaste leather, raw hides, skins, hoofs, horns or bones, first with an alkali under heat, arresting the -action thereof before a glue is formed, then cooling the mass treating the latter with dilute acid mixing the same with sawdust damping this, mixture with a solution of stannate of soda and hide glue, grinding the mass and thoroughl miX-, 

